So do you have a separate cable line ran to the spot of the receiver,or just the one for your satellite? If you have a separate cable line then you just need to insert it into the coaxial port on the back of your 301 labeled "antenna/cable". If you have just the one cable line for satellite,then you either need to run another cable line to the receiver from your cable box/line,,or use a couple of diplexors to send both sat & cable signals to the receiver. Perhaps some of the regular posters on here can post a diagram to help explain the diplexor set up?
As for tuning to your cable stations,you can A) turn off the 301 & watch cable channels,or B) use the tv/video button on your Dish remote to go back & forth between sat & cable,or C) run your satellite through a different input & tune to that input for sat,& antenna input for cable.